It is a known agricultural practice to make use of a double shoot air seeder when seeding a field for depositing both fertilizer and seed into the ground in a single pass over the ground. A double shoot air seeder generally comprises a fertilizer conduit and a seed conduit for conducting fertilizer and seed from respective fertilizer and seed hoppers on the seeder to a plurality of furrowing elements. The furrowing elements are arranged to deposit the seed and fertilizer into the ground at spaced apart locations. This is desirable so as not to provide too much fertilizer to the seed in the early stages of seed growth. It is however desirable to deposit a small amount of starter fertilizer with the seed to assist in the early stages of growth without burning the seed. This is accomplished when using a triple shoot air seeder which is arranged to deposit a small amount of fertilizer with the seed and a further amount of fertilizer spaced from the seed. The replacement of a double shoot air seeder with a triple shoot seeder however is very costly and preferably avoidable.
Canadian Patent No. 1,297,735 to Neumeyer provides a fertilizer divider for dual air seeder systems. The divider comprises an adjustable divider plate which is coupled to the fertilizer metering system such that adjustment of the plate will redirect a portion of the fertilizer into the seed tube in a double shoot air seeder. The divider however includes a complex arrangement of parts which requires tedious installation directly adjacent the metering system as well as some replacement of parts of the seeder. Furthermore, the metering system requires separate adjustment of the amount of fertilizer being deposited into the seed tube and the amount of fertilizer being deposited into the fertilizer tube. This is inconvenient when it is desirable to increase the overall flow rate of both the seed and fertilizer while preserving a constant ratio of fertilizer which is to be diverted into the seed tube.